The present invention is directed to physical structures and methods for controlling the flow of small volumes of liquids through a biosensor. More particularly, the present invention is directed to such physical structures that define a capillary channel and microstructures.
Electrochemical biosensors are known. They have been used to determine the concentration of various analytes from biological samples, particularly from blood. Electrochemical biosensors are described in U.S. Pat. Nos. 5,413,690; 5,762,770; 5,798,031; and 5,997,817 the disclosure of each of which is expressly incorporated herein by reference.
According to the present invention a biosensor is provided. The biosensor comprises a substrate and a cover extending across at least a portion of the substrate. The cover includes a first surface facing the substrate and a second surface. At least a portion of the first surface is removed to define a capillary channel. The capillary channel has a surface energy ranging from about 60 mN/m to about 72 mN/m.
According to another aspect of the invention a biosensor is provided. That biosensor comprises a capillary path defined between a substrate and a cover and at least one microstructure positioned in the capillary path. The at least one microstructure includes a fixed end coupled to either the substrate or the cover and an opposite free end, wherein the free end is metallic.
According to still another aspect of the present invention a biosensor is provided. The biosensor comprises a substrate, electrodes positioned on the substrate, a cover extending across at least a portion of the substrate to define a capillary path, and at least one microstructure positioned in the capillary path. The at least one microstructure includes a fixed end coupled to the cover and an opposite free end, wherein the free end is metallic.
According to still another aspect of the invention a method of forming biosensor is provided. The method comprises the steps of providing a substrate, a reagent for the measurement of at least one analyte, and a cover, the cover including a first surface, exposing the cover to at least one pulse of light of sufficient to ablate the first surface in a predetermined pattern creating a channel, cleaning the first surface of the cover so that the surface energy of the channel ranges from about 60 mN/m to about 72 mN/m, and placing the first surface of the cover upon the substrate to define a capillary path and the reagent is positioned in the capillary path.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.